THE FLOWER 



79 



Immediately above the sepals, and alternating with them, are 

 five bright yellow heart-shaped leaves («) ; these are the petals, 

 the whole collection of which is termed the corolla of the flower. 



Next to the whorl of petals are the stamens (s), of which there 

 are a large number. Each consists of a thin thread-like stalk 

 surmounted by a swollen and elongated tip. In the buttercup 

 the stamens are not arranged in a whorl but in the form of a 

 closely wound spiral round the receptacle ; the whole collection 

 of them is the andraeciuin of the flower. 



Occupying the highest position upon the receptacle is a series 

 of small, green, flask-shaped bodies (c) ; they are hollow and it 



A B 



Fig. 34. — A^ Flower of Buttercup {Ran-uncul-us acris L.), B, 

 Vertical section through the same, r Receptacle of the flower ; in sepal 

 of the calyx ; « petal of the corolla ; s stamen of the androscium ; c 

 carpel of the gynaecium. 



is within them that the seeds of the plant are produced. Each 

 is termed a carpel, and the whole collection is known as the 

 gyncecium ox pistil of the flower. 



3. Although the flower of a plant appears different in many 

 respects from anything we have yet examined it is in reality a 

 form of simple shoot or a stem with leaves upon it. The whole 

 of its parts, however, have been modified to serve the purpose 

 of seed production, and at first sight its likeness to a simple 

 vegetative shoot is not appreciated. 



That a flower is essentially equivalent to a simple shoot with 



